Axial flow fan



Aug. 14, 1945.

N. T. BAUER AXIAL FLOW FAN Filed. Jan. 26, 1945 2 Sheets-Sheet l INVENTOR M/g /m/f/pwm, Q44, v ATT NEYS Aug. 14 1945.

N. T. BAUER AXIAL FLOW FAN v2 Sheets-Sheet 2 Filed Jan. 26, 1943 9 g 4, w 9 K Q z .1, I W, Y W W. f v fl flw 1 X, (x 0 3 5? 6 v INVENTOR fmwzvf/jwwa emu/am, 2 ATT zNEYs Patented Aug. 14, 1945 2,382,535 7 AXIAL FLOW FAN Norman '1. Bauer, Kenmore, N. Y., assignor to Buffalo Forge Company, Buflalo, N. Y., a corporation of New York Application January 26, 1943, Serial No. 473,619

4 Claims.

My invention relates in general to axial flow fans and particularly to that type of fan having adjustable blades.

It is well known to those skilled in the art that in present day fans it is customary to have the periphery of the wheel rim cylindrical in form and to have the lower ends of the blades shaped to fit such cylindrical rim when the blades are set at the predetermined angle in relation to the axis of the wheel. Furthermore, cylindrical casings have heretofore been used, the tip of the blade being made either straight or curved to fit such cylindrical casing when arranged in fixed relation to the wheel axis. Such blades cannot, therefore, be adjusted angularly about their axes upon said rim without causing openings to be formed between the lower ends of the blades and the periphery of the rim. Such an arrangement also causes interference between the tips of the blades and the casing when such adiustment is attempted.

The principal object of my invention has been to provide a fan having a wheel so formed that the blades may be rotated on their axes while fit said wheel member, whereby to permit rotation about the axis while maintaining minimum clearance between the periphery and the blade ends.

A further object has been to provide a, fan wheel so shaped that the entrance of the air into the wheel may be accomplished in a smooth and gentle manner, thereby improving the performance of the fan.

Another object ha been to provide a fan having a casing formed with a spherically-shaped annular recess opposite the tips of the blades, and to form the blade tips with convex surfaces conforming substantially to the spherical recess.

Moreover, because the blades of my fan may be moved about their axes to any desired position without decreasing the efiiciency of the fan, my invention makes it possible to change the direction of air flow through the fan without changing the direction of rotation of the fan wheel; and, furthermore, makes it possible to use the most eflicient sides of the blades when reversing the direction of rotation of the wheel to effect reversal of the air flow.

Furthermore, because the efliciency of my fan is not materially affected by adjustment of the blades, the output of the fan may be varied at will without the use of dampers or shutters; and, when an electric motor is used to drive the fan,

this variation of outlet may be accomplished without the necessity for changing the motor speed, thereby simplifying the motor controls.

Moreover, by means of my invention I canmake a more compact fan, and, because of the sph'erical periphery of the wheel rim, I am enabled to use a much shorter spinner.

Furthermore, because my invention permits a change of fan capacity it is unnecessary for the manufacturer to carry a large number of various sizes in stock in order to meet the demands of the trade.

The above objects and advantages have been accomplished by the device shown in the accompanying drawings, of which:

Fig. 1 is an exterior view, partly in section of an axial flow fan embodying my invention;

Fig. 2 is a fragmentary side elevation of a complete wheel;

Fig. 3 is a fragmentary sectional view taken on line IIIIII of Fig.

Fig. 4 is an enlarged fragmentary sectional view taken on line III-III of Fig. 2;

Fig. 5 is a fragmentary sectional view of a modified form of my invention;

Fig. 6 is a fragmentary side elevation of the form of invention of Fl 5; and,

Fig. 7 is a fragmentary sectional view taken on line VI-VI of Fig. 4.

Referring to the form of invention shown in Figs. 1 to 4, the wheel member I 0 preferably comprises a hub II and a rim I2. The hub II is formed with a suitable bore for the reception of the fan shaft 41. The rim is formed of rim portions I4 and I5, the portion I5 having an annular flange I6 which is connected to the hub II by means of a disc 20. The portion ll of the rim is provided with a flange 2I which preferably lies adjacent the flange I6 of the rim portion I5. Suitable means may be employed for aligning the rim portions I4 and I5, and for convenience, I have shown a ridge 22 formed on the rim portion I5 which engages a groove 23 formed in the rim portion I 4. When in their normal positions as shown in Fig. 4 there are clearance spaces 31 and 38 between the flanges I 5 and 2! and between the ridge 22 and the bottom of the groove 23, respectively, for reasons to be hereinafter described. The flanges I6 and 2| are provided preferably with registering apertures 24, for the reception of 'bolts 25. The portions I4 and I5 of the rim have a combined periphery 38 which forms a part of a sphere and which has its center preferably coincident with the axis of the hub II and located at a point midway the length of the rim. Formed in the periphery 38 of the two rim portions I4 and I 5 of the rim is a plurality of spaced grooves 26 and 30 which form an inwardly extending annular ridge 3| preferably V-shaped in formation.

The blades 32 of my invention are preferably airfoil in form and each of them is provided with a cylindrical base 33 having an outer sphericallyshaped surface conforming substantially to the spherically-shaped surface 33 of the rim periphery. The base ,is formed with an annular V- shaped groove 34 for engagement with the V- shaped ridge 31 of the rim portions. When assembled within the recesses 28 and 30 and with the ridge 3| in engagement with the groove 34, the base 33 may be clamped in position by tightening the bolts 25. As hereinbei'ore pointed out, the spaces 31 and 33 permit movement of the parts i4 and I toward each other to effect the clamping action just described.

The inner end surface of each of the blades i formed with a concave surface 35 preferably forming part of a sphere having its center substantially coincident with the center of the spherically shaped periphery 38 of the rim. The radius of this blade surface is slightly greater than the radius of the periphery 33 so as to provide a slight clearance between these surfaces.

The casing 36 of my fan is cylindrical, as is customary in axial flow fans, and is provided at the place opposite the tips of the blades with a concave recess 40. The surface of the recess 40 also is preferably shaped so as to substantially form a part of a sphere with its center preferably struck from the same center as the radius which forms the spherical surface 38 of the fan wheel. The surface 4| at the tip of each of the blades is also preferably convexly or spherically shaped to correspond to the recess 40, it being necessary to provide only a slight working clearanoe between the tip and the casing.

If desired, the wheel of my fan may be provided with a spinner 42, convex in form, as shown in Figs. 1, 2, and 6, and so shaped that a line drawn tangent to the curvature at the edge will be coincident with a line drawn tangent to the edge of the adjacent spherical surface 38 of the wheel member periphery; thereby providing a streamline connection between these two parts. Suitable fastening means 43 are provided which pass through the spinner and into and through suitable lugs'44 formed on the part I4 of the rim portion.

Referring now to the form of invention shown in Figs. 5 and 6, the wheel member 45 comprises a hub 46 and a rim portion 50 joined together by means of an annular disc 5|. The periphery 52 of the rim portion of the wheel forms part of a sphere having a radius struck preferably from a center lying substantially coincident with the axis of the wheel. A plurality of recesses 53 are provided in the periphery of the wheel, extending inwar ly from each of which is an aperture 54. Arran ed under the rim 50 and in line with each of the apertures in a bearing ring 55 which is carried by the disc 5| and which also is provided with an aperture 53 in registering position with the aperture 54 and preferably of the same diameter.

The blades 60 of this form of invention are each formed with an annular base portion 3| for engagement with one of the recesses 53 of the rim periphery. Extending from each 01' the base portions Si is a stud 62 formed with spaced bearing flanges 63 and 64 and joined by a cylindrical clamping portion 35. The flange 33 engages the aperture 54, and the flange 64 engages the aperture 55, whereby the blade is adjustably mounted.

Each of the blades is provided with a clamp 36 for holding the blade in its adjustable position and for preventing endwise movement thereof. This clamp comprises a lever part II and a cap part II, each formed with a semi-cylindrical recess for clamping engagement with the clamping portion of the blade stud '2, suitable clamping screws 12 being provided for drawing the lever part 13 and cap part II together. The lever part extends preferably toward the edge of the rim 50 where it is provided with a head 13 having its edge surfaces substantially forming a part of a sphere. The rim I0 is provided with bearing pads 14 formed on the inner surface thereof at places where the clamps 86 are disposed. The pads act as stops for engagement with the clamps for holding the blades against axial movement.

An adjusting ring 15 is oscillatably carried by the rim portion 50 of the wheel and is formed in .its periphery with a plurality of notches 13 for the reception of the heads 13 of the lever parts of the clamps. A set screw 11 is carried by the rim portion 50 of the wheel and engages a notch 19 formed in the adjusting ring I5, whereby the ring is limited in its travel and may be locked in the position to which it has been moved when adjusting the blades. A plurality of lugs 30 are formed on the edge of the rim for bearing contact with the outside surface of the ring 15 to retain it in position. The surfaces 8| of the bearing pads 14 against which the inner surface of the ring bears serves to position the ring inwardly. The lugs 30 are preferably the same pitch as the slots 18 so that when assembling the ring the slots are registered with the lugs and the ring is moved axially over them until it contacts the surfaces 8| of the bearing pads, whereupon it is rotated to the position shown in the drawings and the screw 11 is engaged with the slot 19. 1

If desired, graduations may be provided on the periphery of the rim portion adjacent the bases of the blades. In the form of invention shown in Figs. 1 to 3 graduations would be provided for each blade, whereby they may be accurately matched when being adjusted. In the form of invention in Figs. 5 and 6, graduations need be provided for but one blade, since the blades are movable in unison during adjustment.

It will be obvious from the foregoing description that the blades of my invention may be adjusted to any desired position and that the lower end surface of each will remain in conformity with the spherically formed eriphery of the rim portion of the wheel no matter what position the blade may occupy. Furthermore, the sphericallyshaped recess of the casing permits adjustment of the blade while maintaining substantially the same clearance between the casing and the convex surfaces of the blade tips.

While it is preferable to have the periphery of the rim of my wheel member and the casing recess each forming a part of a sphere so that the maximum adjustment of the blades up to 360 may be had, it is obvious that when the contemplated adjustment is of limited amount, minimum clearances between the ends of the blades and rim and easing may be maintained by forming the rim and casing with surfaces which are not truly spherically, but are, for instance, of spheroidal or ellipsoidal shape. Therefore, when I refer in the claims to these surfaces as substantially forming a part of a sphere, it will be understood that the use of other shapes re- Having thus described my invention what I claim is:

1. A fan wheel comprising a wheel member having a periphery soshaped as to form an unbroken part of a sphere, said member being formed through its periphery with a plurality of radial base apertures, a plurality of fan blades rotatably carried by said member, each of said blades being formed with a broad base of cylindrical disc-shape form for engagement with one of the base apertures in said periphery, the top surface of each of said bases being spherically shaped to conform to the periphery of said member, whereby the spherical continuity of said periphery is maintained across its entire width, the under surface of each blade on each side of said base being spherically shaped to conform to the periphery of said ,member, a pair of registering stud apertures formed in said member in alignment with said base aperture, each of said blades being provided with a radially arranged stud extending inwardly from said base and having spa ed bearing surfaces for engagement with one pair of the stud apertures, each of thestuds being formed with a clamping portion between the bearing surfaces thereof, a clamp for each of said blades disposed about the clamping port on of said stud and between said bearing surfaces, means for preventing axial movement of said clamp upon said stud, a lever carried by each of said clamps, an adjusting ring rotatably carried by said member, means for operatively eonnecting said lever to said ring and means for limitin the rotation of said adjusting ring and for looking it in its adjusted position.

2. A fan wheel comprising a wheel member having a periphery so shaped as'to form an unbroken part of a sphere, said member being formed through its periphery with a plurality of radial base apertures, a, plurality of fan blades rotatably carried by said member, each of said blades being formed with a broad base of cylindrical disc-shape form for engagement with one of the base apertures in said periphery, the top surface. of each of said bases being spherically shaped to conform to the periphery of said member, whereby the spherical continuity of said periphery is maintained across its entire width,

. the under surface of each blade on each side of said base being spherically shaped to conform to the periphery of said member, each of said blades being formed with a stud extending inwardly from said base for passage through said rim, each of said studs having spaced bearing flanges, a stud aperture formed in the rim and concentrically arranged with respect to said base aperture for the support of one of said bearing flanges, a bearing lug for each bladecarried by said wheel member and formed with a stud aperture for the bearing support of the other of said bearing flanges, each of said studs being formed with a reduced portion between the bearing flanges thereof, a clamp for each of said blades disposed about the reduced portion of said stud and between said spaced bearing flanges, each of said clamps having bearing contact with the inner surface of the rim adjacent the recess,

a lever carried by each of said clamps, an adjustingring rotatably carried by said member,

means for operatively connecting said levers to said ring, and means for limiting the rotation of said adjusting ring and for looking it in its adjusted position.

3.. A fan wheel comprising a wheel member having a periphery so shaped as to form an unbroken part of a sphere, said member being formed through its periphery with a plurality of radial base apertures, a plurality of fan blades rotatably carried by said member, each of said blades being formed with a broad base of cylindrical disc-shape form for engagement with one of the base apertures in said periphery, the top surface of each of said bases being spherically shaped to conform to the periphery of said member, whereby the spherical continuity of said periphery is maintained across its entire width, the under surface of each blade on each side of said base being spherically shaped to conform to the periphery of said member, a stud aperture formed in said member and spaced inwardly from the periphery thereof, said last mentioned aperture being in alignment with said base aperture, each of said blades being provided with a radially arranged stud extending inwardly from said base and having a bearing surface at its extreme end for engagement with said stud aperture, each of said studs being formed with a clamping portion between the bearing surface and the base thereof, a clamp for each blade disposed about the clamping portion thereof, means for preventing axial movement of the clamp upon the stud, a lever carried by each of said clamps for adjusting the position of said blades, and means for locking said studs in their adjusting positions,

4. A fan wheel comprising a wheel member having a periphery so shaped as to form an unbroken part of a sphere, said member being formed through its periphery with-a plurality of radial base apertures, a plurality of fan blades rotatably carried by said member, each of said blades being formed with a broad base of cylindrical disc-shape form for engagement with one of the base apertures in said periphery, the top surface of each of said bases being spherically shaped to conform to the periphery of said member, whereby the spherical continuity of said periphery is maintained across its entire width.

the under surface of each blade on each side of tioned aperture being in alignment with said base aperture, each of said blades being provided witha radially arranged stud extending inwardly from said base and having a bearing surface at its extreme end for engagement with said stud aperture, each of said studs being formed with a clamping portion between the bearing surface and the base thereof, a clamp for each blade disposed about the clamping portion thereof, means for preventing axial movement of the clamp upon the stud, a lever carried by each of said clamps, an adjusting ring rotatably carried by said member, means foroperatively connecting said levers to said ring, and means for limiting the rotation of said adlusting ring and for looking it in its adjusting position.

NORMAN T. BAUER. 

